Safe and reliable access to major blood vessels and internal organs will be beneficial to patients with cardiovascular disease and cancer. An interventional catheter with forward viewing ultrasound imaging capability will be developed to enable image-guided access to blood vessels and internal organs. Phase 1 experiments demonstrate feasibility of building a high resolution, forward viewing ultrasound array and its ability to yield clinical quality images of ex-vivo tissue. This Phase 2 STTR proposal seeks to build on the Phase 1 results and develop a clinical prototype of the device. Furthermore, we will demonstrate feasibility and safety of the device in its exemplary clinical uses in pre- clinical testing and in proof of concept human studies. We will build a high frequency, small aperture forward viewing ultrasound transducer, characterize it and test it with various iterations of plastc multi-lumen catheters in experimental models and humans. In particular, studies will seek to demonstrate the device ability to track the device tip in real-time and guide it to specific target in the model and human studies. This phase 2 proposal will provide pre-clinical and clinical proof of concept and requisite data to select the best candidate prototype for clinical use and wil position the device for regulatory approval and sale. No such device is currently available in the market and the successful development of a clinically implementable device has immense commercial potential by its ability to contribute significantly to the advancement and expansion of minimally invasive medical procedures.